[Leica] Review: Minolta Dimage Dual Scan III

[Martin Howard <mvhoward@mac.com>]

I was recently humming and haring about which option I should choose: 
cheap digital P&S, expensive digital SLR, or a film scanner.  While at 
first glance option three may have seemed obvious (and in retrospect it 
certainly does), I was out of touch with the cost/performance ratio of 
modern scanners (i.e., those released the past 18 months) that it 
didn't first occur to me.

Fortunately, one of the advantages of a 768kbps Internet pipe plugged 
into the back of your computer is that Google is always available.  A 
few review sites later and I determined that the $300 Minolta Dimage 
Dual Scan III seemed like the perfect choice for me.

Having now used it for about three weeks, I thought it might be time to 
summarize and post my experiences to the LUG, for the benefit of those 
who might be interested in a similar purchase.

I should prefix all this by telling you how I use my equipment.  I 
shoot on (conventional) B&W film which I either develop myself, or have 
commercially developed.  The scanner is used to either produce 72 dpi 
images for the web (about 600-800 pixels along the longest dimension) 
or to produce 5x7" prints on a photo quality inkjet printer.  My reason 
for buying the scanner and printer was to close the photographic loop, 
so that I can shoot film and get prints and, thus, hopefully learn to 
become a better photographer.  In other words, to me, it's a learning 
tool.  I'm not producing 11x14" quad-black prints to mount and hang on 
a wall.  (I've only had the Canon i950 printer for about 1.5 weeks, so 
I'll post a review on that in a while once I've used it some more.)

First off, I'm very impressed by this scanner.  It performs admirably 
for my needs.  Scanning is always done at the maximum resolution of 
2820 dpi, which produces 56 Mb RGB files.  It is ColorSync aware, so I 
am able to use a colour managed process (although I have no hardware 
calibration tool).  I'm using a G4 PowerBook which only has the USB 1.1 
interface, so scanning is a bit slow (especially on the 8x setting), 
but then I'm not in a hurry.

The bundled software comes in two versions.  An "Easy" program which I 
never use and a "Utility" program which affords a great deal of control 
over the scanning process.  Four basic media settings (colour neg, 
colour pos, B&W neg, B&W pos) are the starting point and affect the 
entire six negs in the film strip holder, while other controls allow 
individual control per negative (or, the whole strip, if you choose).

My basic workflow is this: I load the film into the scanner, set the 
film type, and do an index scan.  From this I select the frames that 
I'm interested in scanning and do a preview scan.  The histogram tool 
shows whether the scanner is capturing the full density range.  The 
scanner, by default, scans outside the negative area, thus capturing 
some of the film holder too, which is perfect, because it provides an 
"absolute black" reference point.  As a result, I never crop in the 
scanner, although this is an option.

If necessary, I use the exposure control to lighten or darken the whole 
image.  The histogram shows both Master levels, and individual R, G, & 
B histograms.  An advanced, "Curves"-like gamma/contrast control (for 
those of you familiar with Photoshop) is available and a great tool for 
fine tuning the scan.  For well exposed negatives, I usually don't have 
to do anything, except confirm that things look good.  In short, the 
software makes good initial guesses, that usually only require a little 
tweaking to produce good, clean scans.

Difficult negatives can be handled in two ways.  One is to scan them as 
a positive and then invert the image in Photoshop.  This seems to 
capture a greater range of densities, but is tricky, because all you 
have to learn that a scan that is going to be good looks really dark on 
the monitor when you're tweaking it.

The other trick is to do a two-pass scan: once with the exposure 
setting lower, the other with it set higher (I use -0.5 and +0.5 as 
starting points; +/- 2.0 are the maximum endpoints).  Then, using Curve 
Adjustment Layers in Photoshop, you can recombine the two scans into a 
single image with a much greater range of tones than a single scan 
would enable.  In particular, if there is detail in both deep shadow 
and in sunlit highlight, this is a good option.

I tried Vuescan, but found that it was unstable in Mac OS X 10.2.3 (it 
crashed almost every time I used it) and the interface was obtuse and 
unnecessarily complex compared to the software bundled with the scanner 
itself.

The scanner does not come with advanced dust and scratch removal 
algorithms.  There is an "auto dust brush" feature that seems to work 
better the more you overscan (which is why I have it enabled and the 8x 
multiple scan as default).  Personally, I use a little blower brush on 
the negatives before I scan the film, and the "Healing Brush" or 
"Healing Patch" in Photoshop 7 and it clears up things nicely.  But 
then, as mentioned, I'm not producing museum quality 11x14" prints, so 
for critical use, you'd best try it before deciding.

For my kind of use, and for the $300 price tag, I find the Minolta 
Dimage Dual Scan III to be a steal.  Good quality scans and easy to use 
software mean that I'm very happy with this little workhorse.

M.
  

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